Disk drive device and data rewrite method thereof

ABSTRACT

Embodiments of the present invention help to reduce the occurrence of read hard errors in a hard disk drive (HDD). According to one embodiment, a HDD rewrites data on all data tracks of a block M when the number of write operations to the block consisting of continuous plural data tracks. The HDD further rewrites data on continuous plural data tracks and adjacent to the block. Since the number of write operations is counted every block, a memory area to register the number of write operations can be reduced.

CROSS-REFERENCE TO RELATED APPLICATION

The instant nonprovisional patent application claims priority toJapanese Patent Application No. 2007-080273 filed Mar. 26, 2007 andwhich is incorporated by reference in its entirety herein for allpurposes.

BACKGROUND OF THE INVENTION

Disk drive devices using various kinds of disks, such as an opticaldisk, a magneto-optical disk, and a flexible magnetic disk, have beenknown in the art. In particular, a hard disk drive (HDD) has been widelyused as a storage device of a computer and has been one of indispensabledisk drive devices for current computer systems. Moreover, the HDD hasfound widespread application such as a removable memory used in a movingimage recording/reproducing apparatus, a car navigation system, acellular phone, or a digital camera, as well as the computer, due to itsoutstanding characteristics.

A magnetic disk used in the HDD has a plurality of data tracks formedconcentrically. Each data track has a plurality of data sectors recordedthereon. Further, a plurality of servo data are recorded discretely in acircumferential direction on the magnetic disk. A head element portionsupported by a swinging actuator accesses a desired data sector inaccordance with address information of servo data, which allows datawrite to and data retrieval from a data sector.

The HDD repeats data write and data retrieval operations on a recordingsurface of the magnetic disk. In writing data to a selected track,leakage fields from a head affect the magnetic data on tracks adjacentto the selected track. Repetitive changes in magnetization on the datatrack affect magnetization of adjacent tracks. Therefore, if writingdata on a certain data track is repeated, interference to the adjacenttracks due to the leakage fields from the head and the changes inmagnetization on the data track is repeated so that the user data on theadjacent data tracks may change to cause a read hard error.

In order to prevent such a read hard error, a technique has beenproposed that counts the number of write operations to each data trackand rewrites data of adjacent data tracks if the number of writeoperations exceeds a threshold (for example, refer to Japanese PatentPublication No. 2005-216476 “Patent Document 1”). Specifically, the HDDdisclosed in Patent Document 1 counts the number of write operations tothe adjacent data tracks with respect to each data track. If the numberof writing to the adjacent data track exceeds the threshold, the HDDretrieves the data on the particular data track and rewrites theretrieved data onto the same data track.

The above-described conventional technique effectively preventsoccurrence of a read hard error due to repetitive data write onto acertain data track. However, as the number of the data tracks of themagnetic disk increases, the memory area required for recording thenumber of write operations increases. Although the storage capacity ofthe HDD notably increases, it is required to decrease the memory areafor recording the number of write operations. Besides, it is supposedthat the influence of data write expands to a wider area than theadjacent data tracks with decrease in track pitch.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention help to reduce the occurrence ofread hard errors in an HDD. According to the particular embodiment ofFIG. 3, a HDD 1 rewrites data on all data tracks 115 of a block M whenthe number of write operations to the block M consisting of continuousplural data tracks. The HDD 1 further rewrites data on continuous pluraldata tracks 116 a and 116 b adjacent to the block M. Since the number ofwrite operations is counted every block, a memory area to register thenumber of write operations can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically showing the entire configurationof an HDD according to one embodiment.

FIG. 2 is a view schematically showing servo data and user data on amagnetic disk according to one embodiment.

FIG. 3 is a view showing data tracks to which the number of writeoperations is counted and data tracks to be rewritten according to oneembodiment.

FIGS. 4( a) and 4(b) are views showing other examples of data tracks towhich the number of write operations is counted and data tracks to berewritten according to one embodiment.

FIGS. 5( a) and 5(b) are views showing other examples of data tracks towhich the number of write operations is counted and data tracks to berewritten according to one embodiment.

FIG. 6 is a block diagram schematically showing logic componentsrelating to monitoring of the number of write operations and rewriteoperations in the HDD according to one embodiment.

FIG. 7 shows an example of the rewrite management table according to oneembodiment.

FIG. 8 is a flowchart showing operational steps for counting the numberof write operations and rewriting according to one embodiment.

FIG. 9 is a view showing an example which divides a data track to berewritten to plural sub-sections and rewrites every sub-section.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention relate to a disk drive device and adata rewrite method thereof, and more particularly, to data protectionfrom influence to adjacent tracks caused by repetition of data writeoperation.

An aspect of embodiments of the present invention is a data rewritemethod on a disk recording surface in a disk drive device. This methodcounts the number of write operations with respect to a group of tracksconsisting of continuous plural tracks on a recording surface of thedisk. If the number of write operations exceeds a threshold, the methodrewrites data on each track of the group of tracks and data on a trackadjacent to the group of tracks. Counting the number of write operationsto a group of tracks achieves decrease of the necessary storage area forcounting.

The rewriting data may rewrite data on continuous plural tracks adjacentto the group of tracks. This achieves effective decrease of occurrenceof read hard errors even in a narrow track pitch.

The rewriting data may rewrite data on each of partial tracks of pluraltracks at different operation timings. Moreover, the rewriting data mayrewrite data on the partial tracks of the plural tracks at a timing of adata write operation and/or a data retrieval operation to and from apredetermined region corresponding to the track to be rewritten. Thisachieves prevention of performance degradation.

The counting may count the number of write operations during a seekoperation to a track of the group of tracks. This results in no need ofadditional operation time for counting and achieves to preventperformance degradation.

The rewriting data may refer to the data set registered to be variableand indicating a region which is to be rewritten, and rewrites data ontracks in the number indicated by the data among tracks adjacent to thegroup of tracks. This achieves proper data protection depending on thedesign of the disk drive device or operating conditions.

The disk drive device according to another aspect of embodiments of thepresent invention comprises a controller for counting the number ofwrite operations with respect to a group of tracks consisting ofcontinuous plural tracks on a recording surface of the disk, and a headfor rewriting data on each track of the group of tracks and data on atrack adjacent to the group of tracks if the number of write operationsexceeds a threshold. Counting the number of write operations to a groupof tracks achieves decrease of the necessary storage area for counting.

The head may rewrite data on continuous plural tracks adjacent to thegroup of tracks. This achieves effective decrease of occurrence of readhard errors even in a narrow track pitch.

The head may rewrite data on each of partial tracks of plural tracks atdifferent operation timings. This achieves prevention of performancedegradation. Moreover, the head may rewrite data on the partial tracksof the plural tracks at a timing of a data write operation and/or a dataretrieval operation to and from a predetermined region corresponding tothe track to be rewritten. This achieves to shorten the operation timefor rewriting data on a part of the tracks. In one example, the headrewrites data on the partial tracks of the plural tracks at a timing ofa data write operation and/or a data retrieval operation to and from thegroup of tracks.

The controller may count the number of write operations during a seekoperation to a track of the group of tracks. This results in no need ofadditional operation time for counting and achieves to preventperformance degradation.

The controller may refer to a data set registered to be variable andindicating a region which is to be rewritten, and the head rewrites dataon tracks in the number indicated by the data among the tracks adjacentto the group of tracks under control of the controller. This achievesproper data protection depending on the design of the disk drive deviceor operating conditions.

A disk drive device according to yet another aspect of embodiments ofthe present invention comprises a controller for counting the number ofwrite operations with respect to a group of tracks consisting of a trackor continuous plural tracks on a recording surface of the disk, and ahead for rewriting data on the track or continuous plural tracksadjacent to the group of tracks if the number of write operationsexceeds a threshold. This achieves effective decrease of occurrence ofread hard errors even in a narrow track pitch.

Embodiments of the present invention may help to decrease occurrence ofread hard errors in the disk drive device.

Hereinafter, certain embodiments to which the present invention has beenapplied will be described. For clarity of explanation, the followingdescription and the accompanying drawings contain omissions andsimplifications as appropriate. Throughout the drawings, like componentsare denoted by like reference numerals, and their repetitive descriptionis omitted if not necessary. Hereinbelow, embodiments of the presentinvention will be described by way of example of a hard disk drive (HDD)as an example of a disk drive device. Certain embodiments protect dataon a data track from influence by repetitive data write on a differentdata track.

First, an entire configuration of an HDD is outlined FIG. 1 is a blockdiagram schematically showing the entire configuration of an HDD 1. TheHDD 1 includes a circuit board 20 fixed outside of an enclosure 10. Onthe circuit board 20, circuits such as a read-write channel (RW channel)21, a motor driver unit 22, an integrated circuit hard disk (HDC/MPU) 23of a hard disk controller (HDC) and a multiprocessing unit (MPU), and aRAM 24 are implemented.

In the enclosure 10, a spindle motor (SPM) 14 rotates a magnetic disk 11at a specific angular rate. The magnetic disk 11 is a disk for storingdata. The motor driver unit 22 drives the SPM 14 in accordance withcontrol data from the HDC/MPU 23. Each head slider 12 includes a sliderflying over the magnetic disk and a head element portion which is fixedto the slider and converts magnetic signals to and from electric signals(reading and writing data).

Each head slider 12 is fixed to a tip end of an actuator 16. Theactuator 16, which is coupled to a voice coil motor (VCM) 15, pivotsabout a pivotal shaft to move the head slider 12 above the magnetic disk11 in its radial direction. The motor driver unit 22 drives the VCM 15in accordance with control data from the HDC/MPU 23. An arm electronics(AE) 13 selects a head slider 12 to access (read from or write to) themagnetic disk 11 from a plurality of head sliders 12 in accordance withcontrol data from the HDC/MPU 23 and amplifies read/write signals.

The RW channel 21 extracts servo data and user data from the readsignals obtained from the AE 13 to perform a decoding process. Thedecoded data are supplied to the HDC/MPU 23. The RW channel 21, in awrite operation, code-modulates write data supplied from the HDC/MPU 23and further converts the code-modulated data into write signals tosupply them to the AE 13. In the HDC/MPU 23, an HDC is a logic circuitand an MPU operates in accordance with firmware loaded in the RAM 24.Starting up of the HDD 1, data required for control and data processingare loaded from the magnetic disk 11 or a ROM (not shown). The HDC/MPU23 is an example of a controller and performs entire control of the HDD1 in addition to necessary processes such as head positioning control,interface control, defect management, and the like.

The HDC/MPU 23 transmits read data from the magnetic disk 11 obtainedthrough the RW channel 21 to a host 51. The read data from the magneticdisk 11 is temporarily stored in a read buffer in the RAM 24 beforetransmitted to the host 51 via the HDC/MPU 23. Write data from the host51 are temporarily stored in a write buffer in the RAM 24 via theHDC/MPU 23, and then are transmitted to the magnetic disk 11 via theHDC/MPU 23 at a specific timing. The HDC/MPU 23 according to the presentembodiment particularly controls data rewrite corresponding to thenumber of data write operations.

FIG. 2 schematically shows recorded data on the magnetic disk 11. Asshown in FIG. 2, on the recording surface of the magnetic disk 11, aplurality of servo areas 111 extending radially in the radial directionfrom the center of the magnetic disk 11 at every specific angle and dataareas 112 between the adjoining two servo areas 111 are formed. Theservo areas 111 and data areas 112 are provided alternately at aspecific angle. In each servo area 111, servo data for controllingpositioning of the head slider 12 are recorded. In each data area 112,user data are recorded. The user data and the servo data are recorded onconcentric data tracks and servo tracks, respectively. Data tracks aredivided into a plurality of groups of zones in accordance with radialposition on the magnetic disk 11. A recording frequency is set to eachzone. In FIG. 2, three zones 113 a to 113 c are exemplified.

Hereinbelow, monitoring the number of data write operations and datarewrite operations corresponding to the number of data write operationsaccording to the present embodiment will be described in detail. TheHDC/MPU 23 counts the number of write operations for each of continuous,namely adjacent plural data tracks. In the present specification, agroup of the continuous plural data tracks is referred to as a block.The HDC/MPU 23 rewrites each data track of the block and data tracksadjacent to the block if the number of write operations to one blockexceeds a reference number. The HDC/MPU 23 typically rewrites all of thedata sectors on the data track.

Now referring to FIG. 3, an example of the data rewrite operationaccording to the present embodiment will be described. FIG. 3illustrates continuous 12 data tracks on one recording surface. Each oneof the track numbers (TRACK #) from N−6 to N+5 is assigned to each ofthe data tracks, respectively. In the example of FIG. 3, four continuousdata tracks constitute one block. FIG. 3 illustrates three blocks andeach of the block numbers (BLOCK #), M−1, M, and M+1, is assigned toeach of the blocks, respectively.

When the number of write operations to the block M exceeds the referencenumber, the HDC/MPU 23 rewrites data on all of the data tracks 115 ofthe block M. Further, the HDC/MPU 23 rewrites data on continuous pluraldata tracks 116 a and 116 b adjoining the block M. In the example ofFIG. 3, the number of data tracks to be rewritten on the inner diameterside and the outer diameter side is respectively three.

Since the HDC/MPU 23 counts the number of write operations every block,memory area for registering the number of write operations can bereduced. In the example of FIG. 3, one block consists of four datatracks so that the required memory area will be one fourth comparing tothe case of monitoring the number of write operations every data track.

The HDC/MPU 23 rewrites the continuous plural data tracks 116 a and 116b adjacent to the data block M in addition to each of the data tracks ofthe block M to which the number of write operations exceeds thereference number. Thereby, for example, even if a data write operationto the innermost data track N−2 or the outermost data track N+1 in theblock M is frequently made, data on the data tracks outside of the blockM can be protected.

As the track pitch decreases, influence of data write operation to onedata track may reach a distant data track in addition to an adjoiningdata track. Therefore, rewriting the continuous plural tracks 116 a and116 b adjacent to the block M as shown in FIG. 3 achieves effectiveprevention of data corruption caused by repetitive data write operationeven in a high-density recording HDD.

As described above, it is important to count the number of writeoperations and data rewrite operations on a data track on one recordingsurface because there exists no magnetic interference among data trackson different recording surfaces. FIG. 4( a) schematically illustrates anexample to perform the operation of FIG. 3 with a third head slider HEAD2 in an HDD equipped with four heads (two magnetic disks). One headslider is assigned to one recording surface.

If the track pitch of the magnetic disk 11 is small, it is preferablethat the continuous plural data tracks adjacent to the particular blockare rewritten as described above. However, if the influence of the datawrite operation is limited to one adjacent data track, the HDD 1 mayrewrite only the adjacent data track N−3 in the inner diameter side thanthe block M and only the adjacent track N+2 in the outer diameter sidethan the block M, respectively, as shown in FIG. 4( b).

The number of data tracks constituting a block and the number of datatracks to be rewritten outside of the block are respectively decideddepending on the design of the HDD 1. FIGS. 5( a) and 5(b) illustratesother examples of the number of data tracks constituting a block to be aunit for counting the number of data write operations and the number ofdata tracks to be rewritten. In the example of FIG. 4( a), the number ofcontinuous tracks adjacent to the block to be rewritten is smaller thanthe number of tracks constituting a block. On the contrary, as shown inFIG. 5( a), the number of continuous tracks adjacent to the block to berewritten is the same as the number of tracks constituting a block. InFIG. 5( a), the number of tracks constituting a block and the number ofcontinuous data tracks to be rewritten are respectively four.

Or, as shown in FIG. 5( b), the number of tracks constituting a blockmay be smaller than the number of continuous data tracks to be rewrittenoutside of the block. Or again, as shown in FIG. 5( b), the number ofdata tracks to be rewritten on the inner diameter side and the number ofdata tracks to be rewritten on the outer diameter side may be different.In FIG. 5( b), the number of tracks constituting a block is two and thenumbers of continuous data tracks to be rewritten is four on the innerdiameter side and three on the outer diameter side.

The number of data tracks constituting a block may be differentdepending on the recording surface or the number of data tracksconstituting a block may be different depending on the position on therecording surface. If the block is located on the innermost diameter orthe outermost diameter of the recording surface, the data tracksadjacent to the block is on either of the outer diameter side and theinner diameter side.

As described above, it may be desirable to count the number of writeoperations every block and rewrite the continuous plural data tracksadjacent to the block. However, it may be possible to count the numberof write operations every data track and rewrite the continuous pluraldata tracks adjacent to the data track. This increases the necessarymemory area but can protect the data on the magnetic disk more reliablyfrom the influence caused by a data write operation.

Next, specific processes of monitoring the number of write operationsand the rewrite operations in the HDD 1 according to embodiments of thepresent invention will be described. FIG. 6 is a block diagramschematically showing logic components within the HDD 1 relating tothese operations. FIG. 7 shows an example of a rewrite management table242 for storing data to determine the data tracks to be rewritten. Therewrite management table 242 is provided in the RAM 24. The HDC/MPU 23controls the rewrite operation.

The HDC/MPU 23 comprises a host interface 231, a drive interface 232,and a memory manager 233 as hardware components. The MPU working onfirmware functions as a host interface manger 234, a command executionmanger 235, and the rewrite manger 236. The memory RAM 24 temporarilystores commands and data and has a buffer 241 for temporarily storingthe data in addition to the rewrite management table 242.

The host interface 231 performs actual data transmission to and from thehost 51. The drive interface 232 executes actual data input/output fromand to the magnetic disk 11 (or the RW channel 21). The memory manager233 controls data storage of the RAM (memory) 24 to transfer variousdata between other function blocks in the HDC/MPU 23 and the RAM 24. Thehost interface manager 234 manages the host interface 231 to give andreceive specific notifications or instructions to and from the hostinterface 231.

The rewrite manager 236 controls data rewrite operations based on thenumber of write operations. The rewrite manager 236 registers the numberof write operations in the rewrite management table 242 and executes adata rewrite operation to the magnetic disk 11 referring to the rewritemanagement table 242. The command execution manager 235 controls commandexecutions. The command execution manager 235 controls the driveinterface 232 to control data write operations and data retrievaloperations to and from the magnetic disk 11.

Next, operational steps for counting the number of write operations andrewriting will be described referring to the block diagram of FIG. 6 anda flowchart of FIG. 8. When the host interface 231 receives a writecommand from the host 51 (S11), it transfers the command to the commandexecution manager 235 via the host interface manager 234. Further, thehost interface 231 receives write data from the host 51. The write dataare stored in the buffer 241 via the memory manager 233.

The command execution manager 235 instructs the memory manager 233 andthe drive interface 232 to transfer the write data to the magnetic disk11 (the RW channel 21). The drive interface 232 controls a seekoperation to a target track and a following operation, and a data writeoperation to a target sector (S12) according to instructions from thecommand execution manager 235.

The command execution manager 235 instructs a data write to the magneticdisk 11 as described above, and then transfers the write command to therewrite manager 236. The rewrite manager 236 refers to an addressspecified by the write command and updates the rewrite management table242. Specifically, the rewrite manager 236 increments the counter forthe number of write operations to the block including the data track atthe address indicated by the write data (S13). The rewrite manager 236updates the rewrite management table 242 during the seek operation,which does not require additional operation time for updating and avoidsperformance degradation.

In addition, the rewrite manager 236 determines whether or not theincremented number of write operations onto the block exceeds areference number (S14). If the number of write operations has notexceeded the reference number (N in S14), the rewrite manager 236 willnot execute the rewrite operation. If the number of write operations hasexceeded the reference number (Y in S14), the rewrite manager 236executes the rewrite operation (S15).

The rewrite manager 236 specifies the address to the command executionmanager 235 and instructs it to rewrite the data. The command executionmanager 235 instructs the memory manager 233 and the drive interface 232to execute a data rewrite at the specified address. The rewriteretrieves the data from the specified address of the magnetic disk 11and writes the retrieved data at the same address.

After the rewrite operation has ended, the command execution manager 235notifies the rewrite manager 236 of it. The rewrite manager 236 updatesthe rewrite management table 242 in accordance with the notification.Specifically, the rewrite manager 236 resets the number of writeoperations of the head number and the block number where the rewriteoperation has ended to the initial value (S16).

There are some ways to count the number of write operations to a blockconsisting of continuous plural data tracks. One example counts thenumber of write operations every seek under one command. That is, if aseek operation to a target track is performed for a data writeoperation, the rewrite manager 236 increments the number of writeoperations to the target track. The number of write operations isincremented by one regardless of the number of data sectors to bewritten.

If another seek operation to another target track is performed in a datawrite operation to the address specified by one write command, therewrite manager 236 increments the number of write operations to theblock where the another target data track is included. If the addressspecified by one write command contains a plurality of data tracks inone block, one way is that the number of write operations to the blockis assigned to be one. The number of write operations to each blockincreases by one every write command including the block.

The user data rewrite operation (S15) preferably divides plural datatracks to be rewritten into plural sub-sections and rewrites each of thesub-sections at a different timing. FIG. 9 is an example that dividesten data tracks to be rewritten into five sub-sections 117 a to 117 e byevery two data tracks. The rewrite manager 236 rewrites each of thesub-sections 117 a to 117 e at a different timing.

In one example, the rewrite manager 236 rewrites each of thesub-sections 117 a to 117 e in data write operations and/or dataretrieve operations to and from the block M which is the reference forcounting the number of write operations. For example, the rewritemanager 236 executes the rewrite operation to the sub-section 117 a atthe timing of the write operation by which the number of writeoperations has just exceeded the reference number. The rewrite manager236 executes the rewrite operation to the sub-section 117 b at thetiming of the next write operation to the block M. The rewrite manager236 executes the rewrite operation to the sub-section 117 c at thetiming of another next write operation to the block M.

In this way, the rewrite manager 236 sequentially rewrites to each ofthe sub-blocks 117 a to 117 e at the timing of the write operations tothe block M. The rewrite operations can be performed every data writeoperation to the block M, every data retrieval operation, or the both ofthe data retrieval and writing operations. In case that rewriteoperations to all of the data tracks are performed at one operationtiming, it may take much time to perform the operations and lead toperformance degradation.

The performance degradation can be avoided by dividing the data tracksto be rewritten and rewriting to every part of the data tracks over aplurality of operation timings as described above. Since the data trackto be rewritten is present close to the block M, the operation time forthe rewrites can be shortened.

For easiness of control and effectiveness in performance maintenance, itis preferable to rewrite each of the sub-sections at every accessoperation to the block M which is the reference for counting the numberof write operations as described in the above example, but other waysmay be proposed. For example, one sub-section may be rewritten at atiming of access operation (write or retrieve operation) to a blockincluding an area to be rewritten, that is, any one of the blocks M−1,M, and M+1 in the example of FIG. 8. Or, if the order of thesub-sections to be rewritten has been determined, a sub-section may berewritten at a timing of access operation to the block including thesub-section.

As in the above examples, in write and/or retrieve operations to/frompredetermined area from/to the data tracks 115, 116 a, and 116 b to berewritten, rewrite to each of the sub-sections achieves to rewrite eachof the sub-sections in an access operation (write or retrieve operation)to a vicinity of the sub-sections to be rewritten and to shorten theoperation time.

In an HDD 1 in which the performance degradation does not become aproblem, all of the data tracks may be rewritten. For example, if thenumber of write operations to a subject block exceeds the referencenumber, all of the data tracks may be rewritten in the data writeoperation at that time. The number of data tracks constituting asub-section may be a single or plural, and the number of data tracks ineach sub-section may be the same or different values.

The number of data tracks to be rewritten is preferably variable and canbe set. Specifically, in the example of FIG. 4, the numbers of datatracks of a group of data tracks 116 a and a group of data tracks 116 bmay be able to be set individually. The region where the influence ofthe data write operation reaches may change depending on the design orconditions of the HDD. Therefore, setting the region to be rewritten toa preferable value can achieve data protection and excellentperformance.

The number of data tracks is determined for the inner and outer diametersides integrally or can be determined individually. The rewrite manger236 refers to the preset data and rewrites the data track whose numberthe data indicates. The data can be set in the manufacture of the HDD 1or by the HDC/MPU 23 according to the predetermined conditions.

As set forth above, the present invention is described by way of theparticular embodiments but is not limited to the above embodiments. Aperson skilled in the art can easily modify, add, and convert the eachelement in the above embodiments within the scope of the presentinvention. For example, the control of the embodiments can be applied toa disk drive device utilizing a disk other than the magnetic disk.

1. A data rewrite method on a disk recording surface in a disk drive device, the method comprising: counting the number of write operations with respect to a group of tracks consisting of continuous plural tracks on a recording surface of the disk; rewriting data on each track of the group of tracks and data on a track adjacent to the group of tracks if the number of write operations exceeds a threshold, wherein the rewriting data rewrites data on each of partial tracks of plural tracks at different operation timings; and resetting the number of write operations with respect to said group of tracks to an initial value after said rewriting without maintaining a rewrite count related to the rewriting of said data.
 2. The method according to claim 1, wherein the rewriting data rewrites data on continuous plural tracks adjacent to the group of tracks.
 3. The method according to claim 1, wherein the rewriting data rewrites data on the partial tracks of the plural tracks at a timing of a data write operation and/or a data retrieval operation to and from a predetermined region corresponding to the track to be rewritten.
 4. The method according to claim 1, wherein the counting counts the number of write operations during a seek operation to a track of the group of tracks.
 5. The method according to claim 1, wherein the rewriting data utilizes a variable data set to indicate a region which is to be rewritten, and rewrites data on tracks in the number indicated by the data among tracks adjacent to the group of tracks.
 6. A disk drive device comprising: a controller configured to count a number of write operations with respect to a group of tracks consisting of continuous plural tracks on a recording surface of the disk, wherein the controller refers to a data set registered to be variable and to indicate a region which is to be rewritten; a head for rewriting data on each track of the group of tracks and data on a track adjacent to the group of tracks if the number of write operations exceeds a threshold, wherein the head rewrites data on tracks in the number indicated by the data among tracks adjacent to the group of tracks under control of the controller; and said controller configured to reset the number of write operations with respect to said group of tracks to an initial value after said rewriting without recording the rewriting of said data.
 7. A disk drive device according to claim 6, wherein the head rewrites data on continuous plural tracks adjacent to the group of tracks.
 8. The disk drive device according to claim 6, wherein the head rewrites data on each of partial tracks of plural tracks at different operation timings.
 9. The disk drive device according to claim 8, wherein the head rewrites data on the partial tracks of the plural tracks at a timing of a data write operation and/or a data retrieval operation to and from a predetermined region corresponding to the track to be rewritten.
 10. The disk drive device according to claim 9, wherein the rewriting data rewrites data on the partial tracks of the plural tracks at a timing of a data write operation and/or a data retrieval operation to and from the group of tracks.
 11. The disk drive device according to claim 6, wherein the controller counts the number of write operations during a seek operation to a track of the group of tracks.
 12. A disk drive device comprising: a controller configured to count a number of write operations with respect to a group of tracks consisting of a track or continuous plural tracks on a recording surface of the disk; a head for rewriting data on the track or continuous plural tracks adjacent to the group of tracks if the number of write operations exceeds a threshold, wherein the head rewrites data on each of partial tracks of plural tracks at different operation timings in the data rewrite operation; and said controller configured to reset the number of write operations with respect to said group of tracks to an initial value after said rewriting without maintaining a rewrite count related to the rewriting of said data.
 13. The disk drive device according to claim 12, wherein the data rewrite operation rewrites data on the partial tracks of the plural tracks at a timing of a data write operation and/or a data retrieval operation to and from a predetermined region corresponding to the track to be rewritten.
 14. The disk drive device according to claim 12, wherein the controller utilizes variable setting data to indicate a region to be rewritten; and the head rewrites data on tracks adjacent to the group of tracks and in the number indicated by the setting data under control of the controller. 